Exam2

Divergent Boundaries: Plates moving apart

- Crust types: Oceanic/Oceanic & Continental/Continental

-Ocean/oceanic: New sea floor created

-Process: Sea floor spreading

-Features: Mid-ocean ridge, volcanic arc, young lava flows

-Examples: Mid-Atlantic ridge

-Continental/Contiental: Continental rifting

-Process: As new continent splits apart, new sea floor is created

-Features: rift valley, volcanoes, young lava flows

-Examples: East African rift valleys

Convergent Boundaries: Plates moving together

-Crust Types: Oceanic/continental, Oceanic/oceanic, Continental/continetal

-Oceanic/continental: Old sea floor destroyed

-Process: subduction

-Features: trench, volcanic arc on land

-Examples: Peru-chile trench

-Oceanic/Oceanic: old sea floor destroyed

-Process: Subduction

-Features: trench, volcanic arc islands

-Example: Mariana Trench

-Continental/Continental:

-Process: Collision

-Features: Tall Mountains

-Example: Himalaya mountains

Transform boundaries: Past each other

-Oceanic:

-Process: transform faulting

-Features: fault

-Example: Mendocino Fault

-Continental:

-Process: transform faulting

-Features: fault

-Example: San Andreas Fault

Examples of Marine Provinces:

Continental Margin:

-Active Continental Margin: West Coast of America

-Passive Continental Margin: East Coast of America

Abyssal Plane Example: The Sohm Plain

Mid-Ocean Ridge example: Mid-Atlantic Ridge

Submarine canyons: Created by erosive turbidity currents

-Found on slope of continental margin

-Example: Monterey Canyon

Turbidity Currents: Deposit sediment at base of continental slope

- Carry sediment from shallow to deeper area like continental slope or deep-sea fans

Turbitide deposits: Creates deep sea fans that merge to create gentle sloping continental rise

Turbidity Sediments: layered sedimentary rocks form by deposition of turbidity currents

-Graded bedding: sediment size progressively decreases from coarser material (sand) at base to finer material at top of each layer

Abyssal Plains: flat region of ocean floor

-typically located at base of continental rise with gentle slope

Seamounts: pointed submerged inactive volcano

- originate at hot spot or spreading center

Tablemounts: flat submerged inactive volcano

- originate at hot spot or spread center

Volcanic Arcs:

- curved chain of volcanoes formed at convergent boundaries

- associated with deep-sea trenches

Fracture zones:

- seismically inactive transform fault

- occur beyond the segments of the mid-ocean ridge

Transform faults:

- active transform plate boundaries that occur between segments of mid-ocean ridges

Origins of four categories of Marine Sediment:

-Lithogenous: rock material from continents, volcanic eruptions, blow dust

-Characteristics: created by weathering from water, temperature, chemical effects breaking down rocks

-Transported by erosion, streams, wind, glaciers

-Primarily accumulates: Continental margins, neretic zone

-Biogenous:

-Calcium Carbonate: CaCo3

-Calcite & aragonite

-Produced by: Coccolithophores and foreminifera

-Calcareous ooze deposited on the mid-ocean ridge above the CCD

-At CCD line, calcareous ooze is covered and protected by abyssal clay and SiO2 ooze

-Sea floor spreading moves calcareous ooze beneath CCD into deep water

-Calcite secreting organisms live in warm surface waters

-Calcareous ooze accumulated along mid ocean ridge

-Found along shallower areas of ocean floor beneath warm surface water

-Low latitudes

-Siliceous: SiO2

-Silicon Dioxide, silica, quarts, sand grains

-Silica-secreting organisms live in cold surface waters created by upwelling and associated with high productivity

-High latitudes

-Produced by: Diatoms and Radiolarians

-Hydrogenous:

-Composition from precipitation from chemical reactions at hydrothermal vents

-Metal sulfides: iron, nickel, copper, zinc, silver

-Manganese nodules

-Hydrothermal vents created cloud of fine metal rich particles

Cosmogenous: meteorites

Neritic Sediment: accumulates rapidly on continental shelf, slope and rise

-Beach deposits, continental shelf deposits, turbidity deposits, glacier deposits

-Rocks

-Coarse grained

Pelagic sediment: accumulated slowly on ocean floor

-Fine grained

-Volcanic ash and windblown dust

-Abyssal clay

Hydrothermal Vents: Found in mid-ocean ridge or subduction zone

-Formed when seawater goes into fissures in ocean crust near spreading centers or subduction zones

- Seawater is heated by magma and reemerges to form vents